| Facility agriculture is an important direction of the development of modern agriculture in China. The cultivated areas of facility crops reached more than3million hectares in2009, which accounts for more than86%of the world total facility crop areas. China has become the world’s first facility agriculture country. In recent years, facility agriculture presents rapid development in Jiangsu Province. The facility agriculture areas reached565million acres in2010. However, in winter and spring, spare sunlight is the main meteorological disaster of facility agriculture in Jiangsu Province. Therefore, to launch the study of early warning for facility tomatoes in Jiangsu Province could provide scientific basis for the produce of facility tomatoes and environment management. This study, first of all, we designed artificial controlled experiments to study the influence of spare sunlight stress intensity for the photosynthetic characteristic, chlorophyll fluorescence dynamic parameters and anti-oxidative enzymes activities of facility tomatoes, thus we could defined grade level to spare sunlight disasters on facility tomatoes. Then the spare sunlight distribution rules of facility agriculture in Jiangsu Province were researched by using many years’metrological data. On this basis, we developed early-warning system for facility spare sunlight disasters by making use of computer language of C#. The main conclusions of the study are as follows:(1) The chlorophyll-a content in tomato leaves reduced with the spare sunlight days increased under the spare sunlight stress. The chlorophyll-a content in tomato leaves diminished25.3%than the control group after9days spare sunlight treatment。 chlorophyll-b and carotenoids content in tomato leaves increased with the spare sunlight days increased, the chlorophyll-b and carotenoids content in tomato leaves15.7%and30.5%less than the control group respectively. The maximum photosynthesis rates、light saturation point、apparent quantum yield were all reduced with the spare sunlight stress days increased, while the light compensation point increased with the treatment days increased. The maximum photosynthesis rates of the tomatoes under1day、3days、5days spare sunlight treatment were near the control group after regular light recovery for6days、10days、16days respectively, while the maximum photosynthesis rates of the tomatoes under7days and9days spare sunlight treatment were53.0%and13.8%of the control group respectively after regular light recovery for16days.(2) PSII intrinsic photochemical efficiency (Fv/Fm) and electron transport rate (ETR) of the tomato leaves under spare sunlight stress were lower than the control group significantly; both of them were reduced with the spare sunlight time increased. While the non-photochemical quenching (qN) contrary to that. The Fv/Fm and qN of tomatoes under spare sunlight stress from1to5days could both reach the control level after regular light recovery for12to16days. While Fv/Fm of tomatoes under spare sunlight stress for7and9days were27.3%and71.4%lower than control group respectively, qN were14.8%and48.1%higher than the control group respectively.(3) The SOD activity in tomato leaves increased first and then reduced with the spare sunlight stress days increased, the CAT activity and the contents of soluble protein reduced, while the MDA content increased. The antioxidant capacity of tomatoes reduced significantly, the senescence degree of leaves increased. The system structure and function of the cell membrane were injured seriously. The photosystem activity lost restorability.(4) The maximum photosynthesis rates Pgmax and fluorescence parameters Fv/Fm were used to define the spare sunlight stress level:Spare sunlight for1to2days was mild disaster (Ⅰ level),3to4days was moderate disaster (Ⅱ level), more than5to6days was serious disaster (Ⅲ level), spare sunlight for more8days was severe disaster (Ⅳ level)(5) Combing the facility agriculture spare sunlight disasters index, counted and analyzed monthly, quarterly and annual change characteristics for the occurrence of the spare sunlight meteorological disasters in Jiangsu Province by the use of50years’day by day meteorological data from1960to2009, these data came from54 meteorological data in Jiangsu Province. Based on the interpolation of known observation data, the spatially continuous distribution of raster data were obtained to realize data grid, spatial distribution maps of spare sunlight disasters in Jiangsu Province were gained by using the inverse distance weighted interpolation method. The most serious annual disasters happened in winter, nearly accounted for half the yearly disasters, while the least in summer. The spare sunlight disasters in the south of the Changjiang River were more than that in the north of the Changjiang River. For the past50years, the frequency of occurrence for spare sunlight disasters changed little before1990, while the frequency of occurrence and intensity for spare sunlight disasters had the increasing tendency after1990.(6) The study based on the developing platform of C#、Oracle data base and ArcGIS Server, adopted Ajax asynchronous real time furbish technology、WEBGIS technology、data visualization technology, by making use of established tomato spare sunlight index, facility tomato spare sunlight disaster early warning system for Jiangsu Province was gained, facility microclimate monitor and real time distribution of spare sunlight disaster early warning information for county level were realized. |
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